Induced draft apparatus



Oct. 11, 1932; H. w. PFEFFER 1,882,519

INDUCED DRAFT APPARATUS Filed April '21. 1927 4 Sheets-Sheet 1 E 44 25 g I Oct. 11, 1932. H. w. PFEFFER I INDUCED DRAFT APPARATUS Filed April 21. 1927 4 Sheets-Sheet 2 3mm j 157%;6W

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Oct. 11, 1932. H. w. PFEFFER 1,882,519

INDUCED DRAFT APPARATUS Filed April 21. 1927 4 Shets-Shet s Oct. 11, 1932. H. w. PFEFFER INDUCED DRAFT APPARATUS Filed April 21, 1927 4 Sheets-Sheet 4 gwuwntoz Patented Oct. 11, 1932 UNITED STATES PATENT OFFICE HENRY W. PFEFFER, OF NARBERTH, PENNSYLVANIA, ASSIGNOR, BY MESNE ASSIGN- MENTS, TO AMERICAN BLOWER CORPORATION, OF DETROIT, MICHIGAN, A COK- IPORA'IION OF DELAWARE INDUCED DRAFT APPARATUS Application filed April 21,

This invention relates to improvements in induced draft apparatus for furnaces, stoves, or the like, and similar purposes.

An object of the invention is to improve this class of apparatus in regard to protecting the exhaust fan shaft, and the power connection or means against excessive heat from the hot gases, and to provide a more durable, satis factory induced draft apparatus.

Particularly important novel characteristics of the invention reside in the special construction and means provided for insulating the side of the exhaust fan, and in the particular connection provided between the fan and power means for dissipating and preventing the transmission of heat to the drive shaft and associated arts, and whereby the working parts are e ciently protected from injury by the heat of the gases.

The invention, with other objects and advantages thereof, and the particular con"- struction, combination and arrangement of parts comprising the same will be understood from the hereinafter contained detail description when considered in connection with the accompanying drawings forming part hereof and illustrating embodiments of the invention.

In the drawings:

Figure 1 is a perspective view of a household furnace equipped with induced draft apparatus constructed in accordance with the present invention.

Fig. 2 is a part section and side elevation of the exhaust fan, the casing for the fan an the motor.

Fig. 3 is a detail side elevation of the fan and means for connecting the same to the motor shaft.

Fig. 4 is a detail end elevation of the fan.

Figs. 5, 6, 7, and 8 are detail sections and end elevations respectively of the protector plates on one side of the exhaust fan.

Fig. 9 is a part section and part side elevation of a slightly modified form of the connection between the fan and motor.

\Vhile specific embodiments of the invention are illustrated in the drawings, it will of course be understood that changes and variations may be made intlle particular con- 1927. Serial No. 185,617.

structions shown and the invention may be embodied in other forms, as will appeal to those skilled in the art and falling within the scope of the appended claims, without departing from the spirit of the invention.

Referring to a detail description of the particular embodiment of the invention illus trated Figures 1 to 8 of the drawings, 1 designates a casing adapted to contain a fan Wheel 2 and to be connected with the smoke flue of a furnace for drawing the combustion gases from the furnace and increasing the draft, the construction of casing and fan wheel shown bein generally that of one of the well known forms of centrifugal fans having an inlet 3 and an outlet 3, the fan wheel 2 being of multi-bladed drum formation comprising blades 6, a supporting back plate 5 and an annular rim part 4, the construction here shown being formed from a continuous piece of sheet metal, the blades 6 being punched out from a cylinder.

7 designates an electric motor located at one side of the casing 1 for driving the fan wheel 2, the casing l and the motor 7 being mounted on a supporting base 8 of wood or other suitable material.

The invention comprehends a drive shaft connection between the fan wheel and motor comprising aligned coupling portions arranged in separated relationship out of contact with each other with a space therebetween, and a plurality of portions bridging the space between and connecting the coupling portions at different points thereabout for rotation together. Referring particu larly to Figures 2 and 3 of the drawings the connection between the fan wheel and motor is shown as comprising inner aligned spaced coupling portions in the form of hubs 9, 10, connected by a plurality of outer blades or wing portions 11, each having a portion 11 extending radially in the plane of the hub 10, and a portion 11 extending at an inward inclination in the direction of the fan casing 1 from the outer end of the first mentioned portion 11 to the other hub 9. In this instance, the hub 9 of the connection or cou pling is secured directly to and constitutes the hub-of the fan wheel 2, said hub being pling provided with a flange 13 at its outerend a ainst' which the back plate 5 of the fan wieel fits and is secured by rivets 14 or the like. The hub 9 is tubular or hollow and the back plate 5 of the fan wheel has a central opening 5 and fits over an annular shoulder or boss 15 on the flange 13, the central opening 5 of the back plate 5 being disposed in alignment with the opening in the hub 9. The other coupling portion or hub 10 fits upon and is firmly secured by a screw 16 or other suitable means to the shaft 17 of the motor 7, the construction constituting a support for the fan wheel 2 from the shaft 17 of the motor as well as a drive connection between the parts. The connection or coucomprising the hubs 9, 10 andwing portions 11 is constructed from aluminum or other suitable material, the same conveniently taking the form of a casting.

In accordance with the invention the easing 1 is provided with insulating means to protect the motor 7 and associated parts from the heat of the gases passing through the casing, said means comprising plates or wall portions of metal or other suitable material disposed at the drive side of the casing, the plates being arranged in superposed relationship separated to provide an air space therebetween. In the particular construction illustrated in the drawings, the side wall 1 of the casing is provided with a circular opening 1 and secured to the casing to extend over said opening are a plurality of plates,

in this instance, two plates 18, 19, being shown, secured at their marginal portions to the side wall 1 in superposed spaced relation. The plates 18, 19, which with a separating ring or washer 20 of any suitable material, are secured to the casing by bolts 21 or equivalent means, have central openings 18, 19, through which the hub 9 of the fan wheel 2 extends to the exterior of the casing, said openings of the plates as shown being of a size sufiicient to provide for the spacing of the central portions of the plates 18, 19 a substantial distance from the outer face of the hub 9, an opening to the air ace 22 between the plates 18, 19 being provided at the central part of said plates around the hub 9. The plates 18 and 19 may be and preferably are respectively provided with inner inwardly dished portions 18*, 19".

By the particular construction and arrangement of parts hereinbefore set forth, the motor and the supporting and drive shaft connection for the fan are protected in an eflicient way from injury by the heat of the gases. The superposed protector plates with an air space therebetween afl'ord simple and efficient heat insulating means. The special connection or coupling between the fan and motor provides for'an air gap between the hub of the fan wheel and the end of the motor shaft which, as will be appreciated, is highly effective in preventing the transmission of heat from the hub of the fan wheel to the motor shaft, and the blades or wings of the connection or coupling of course act to dis- I sipate heat by radiation and said blades or Wings also act to cause a circulation of air about the separated hub portions, and over the fan casing and motor, which serves to carry off or dissipate heat from the parts. The spacing of the hub of the fan from the central part of the protector plates permits of free circulation of 'air from the outside around thehub of the fan, and the hub of i the fan will be further cooled by circulation of air from the outside through the opening of the hub to the interior of the fan.

In the particular embodiment of the intherefor, in which is interposed the casing 1 containing the fan wheel 2, the pipe section 44 being connected with the inlet 3 of the fan casing 1 and the pipe section 45 being connected with the outlet 3 of the fan caslng.

In Figure 9 of the drawings is illustrated a slightly modified form of connection providing for coupling two arts together for rotation and preventing t e transmission of heat from one to the other. This modified form of connection or coupling is the same in principle and operation as the construction illustrated Figures 2 and 3 of the drawings, previously described, except that in this instance the same is used for directly connecting two shafts instead of being directly connected with the fan wheel as in the construction previously described.- In Figure 9 of the drawings 49 and 50 designate the aligned spaced coupling tubular hub portions, and 51 are the outer blades or wing portions bridging the space between and connecting the hubs 49 and 50. 52 and 53 are aligned shafts over which the tubular hubs 49, 50 respectively fit and are secured by screws 53 or equivalent fastening means, the ends of the shafts 52, 53 being out of contact separated by an air gap.

What I claim is:

1. An induced draft apparatus including a casing having an inlet and. an outlet adapted to be connected with an exhaust conduit for hot gases and the like, a fan wheel within the casing; a motor outside the casing for rotating the fan wheel, and a coupling between the motor and fan wheel comprising aligned spaced coupling portions and a plurality a casing having an inlet and an outlet adapted to be connected with an exhaust conduit for hot gases and the like, a fan wheel within the casing, a motor outside the casin for rotating the fan wheel, and coupling etween the motor and fan wheel comprising aligned spaced coupling portions and a plurality of members bridging the space between and connecting the coupling portions together at different points thereabout, said members comprising blade portions to create a circulation of air about the spaced coupling portions. 7

3. An induced draft apparatus including a casing having an inlet and an outlet adapted to be connected with an exhaust conduit for hot gases and the like, a fan wheel within the casing, a motor outside the casing for rotating the fan wheel, and a coupling between the motor and fan wheel, said coupling being of open formation and having wing portions to create a circulation of air about the said casing and motor.

4. An induced draft apparatus including a casing having an inlet and an outlet adapted to be connected with an exhaust conduit for hot gases, a fan wheel within the casing, a motor outside the casing for rotating the fan wheel, a coupling between the motor and fan wheel comprising aligned spaced coupling portions and a plurality of members bridging the space between and connecting the coupling portions together at different points thereabout, said members being of blade formation and having portions inclined to the axis of rotation of the inner coupling portions toward the fan wheel, adapted to create a circulation of air laterally and outwardly toward the casing.

5. An induced draft apparatus including a casing having an inlet and an outlet adapted to be connected with an exhaust conduit for hot gases, a fan wheel within the casing, a motor outside the casing for rotating the fan wheel, a coupling between the motor and fan wheel comprising aligned spaced coupling portions and a plurality of blade members bridging the space between and connecting the coupling portions together at different points thereabout, each of said blade members having a portion extending radially from and disposed in the plane of one of said coupling portions, and an inclined portion extending from the outer part of said first mentioned portion to the other coupling portion.

6. An induced draft apparatus including a casing having an inlet and an outlet adapted to be connected with an exhaust conduit for hot gases, said casing having an opening in the side wall thereof, a fan wheel within the casing having a hub disposed at said opening, means for rotating the fan wheel including a rotary shaft outside the casing in alignment with the hub of the fan wheel and spaced therefrom, and a plurality of wing portions bridging the space between the hub of the fan wheel and said shaft and connecting said portions together at different points thereabout. 4 7. An induced draft apparatus including a casing having an inlet and an outlet adapted to be connected with an exhaust for hot gases, said casing having an opening in a side wall thereof, a fan wheel within the casing, said fan wheel being of drum formation having a back plate provided with a central opening and a tubular hub part secured thereto, the opening in the hub part and the opening in the back plate being in alignment and the hub being disposed at said openin in the easing, means for rotating the fan w eel including a rotary shaft outside of the casing in alignment with and spaced from the hub of the fan wheel, and a plurality of blade portions bridging the space between the hub of the fan and said shaft and connecting said parts together at-difierent points thereabout. 8. An induced draft apparatus including a casing having an inlet and an outlet adapted to be connected with an exhaust conduit for hot gases, said casing having an opening in the side wall thereof, a fan wheel within the casing, said fan wheel having a tubular hub part extending through the said opening in the side wall of the casing and providing a passage therethrough from the exterior to the interior of the casing, means for rotating the fan wheel including a rotary shaft outside the casing in alignment with and spaced from the hub of the fan wheel, and a lurality of blade portions bridging the space etween the hub of the fan wheel and said shaft and connecting said parts together at different points thereabout.

9. An induced draft apparatus including a casing having an inlet and an outlet adapted to be connected with an exhaust conduit for hot gases, a fan wheel in the casing, a motor located at one side of the casing to rotate the fan wheel, a drive shaft connection between the motor and the fan wheel, heat insulating means at the side of the casing at which the motor is located, said means comprising superposed side plates on the casing having portions separated to provide an air space therebetween, and blade portions associated with the drive shaft connection adapted to create a circulation of air over the outer of said side plates.

10. An induced draft apparatus includin a casing having an inlet and an outlet adapted to be connected with an exhaust conduit for hot gases, said casing having a side wall comprising a plurality of plates arranged in su perposed spaced relation, said plates having aligned central openings, a fan wheel within the casing, a motor for rotating the fan wheel and the central portions of said plates located outside the casin at the side thereof havin the plurality 0 super osed plates, and a rive connection between t e motor and fan wheel, said drive connection extending through the central openings of said lates mg spaced from the drive connection to leave an open area between the drive connection and plates and intothe space between said plates.

11. An induced draft ap' aratus including a casing having an inlet an an outlet adapted to be connected with an exhaust conduit for hot gases, said casing having a side wall comprising a pluralit of plates arranged in superposed spaced re ation, said plates having aligned central openings and bemg dished inwardly toward the interior of the casing, a fan wheel within the casing, a motor for rotating the fan wheel located outside the easing at the side thereof having the lurality of super osed plates, and a drive s aft connection between the motor and fan wheel, said shaft connection extending through the central openin s of said plates and the central portions 0 said plates being spaced from the shaft connection to leavean open area between the shaft connection and plates and into the space between said plates.

12. An induced draft apparatus including a casing having an inlet and an outlet adapted to be connected with an exhaust conduit for hot gases, said casing having a side wall comprisin a plurality of plates arranged in superpose spaced relation, said plates having aligned central openings, a fan wheel within the casing, a motor for rotating the fan wheel located outside the casing at the side thereof having the plurality of superposed plates, and a drive connection between the motor and fan wheel, said connection including a portion extending through the central opening in said plates in spaced relation therewith, and said drive connection having blades adapted to cause a circulation of air over the outer of said plates. 1

13. An induced draft apparatus including a casing having an inlet and an outlet adapted to be connected with an exhaust conduit for hot gases, said casing having a side wall comprising a plurality of circular metal plates arranged in superposed spaced relation and secured at their marginal portions to the casing, said plates having aligned central openings, a fan wheel within the casing, a motor for rotating the fan wheel located outside the casing at the side thereof having the plurality of superposed plates, and a drive connection between the motor and fan wheel, said drive connectionextending through the central openings of said plates and the central portions of said plates being spaced from the drive connection to leave an open area between the drive connection and plates and into the space between the plates.

14. An induced draft apparatus including a casing having an inlet and an outlet adapted to be connected with an exhaust conduit for -hot gases, said casing having a wall at one ings of said plates and the central portions of said plates being spaced from the drive connection to leave an open area between the drive connection and plates and into the space between the plates.

15. An induced draft apparatus including a casing having an inlet and an outlet adapted to be connected with an exhaust conduit for hot gases, said casing having a wall at one side comprising a plurality of plates arranged in superposed spaced relation, said plates having aligned openings centrally thereof, a fan wheel within the casing having a hub portion extending through the central openings of said plates in spaced relation therewith, said hub being tubular providing a passage therethrough from the exterior to the interior of the casing, a motor for rotating the fan wheel located outside the casing and having a shaft extending in alignment with and spaced from the hub of the fan wheel, and a plurality of blade portions bridging the space between the hub of the fan wheel and the shaft and connecting said parts together at different points thereabout.

16. In ahigh temperature exhaust blower, a casing, a shaft extending therethrough, a shaft bearing externally thereof, a fan on said shaft in said casing, and a cooler fan on said shaft spaced from the blower fan and disposed between said bearing and said blower fan, at least a portion of said cooler fan being exposed toward said bearing to permit direct circulation of air influenced by said fan over the bearing.

17. In a high temperature exhaust blower, a casing, a shaft extending into said casing, a fan on said shaft within the casing, a shaft bearing externally of the casing, and means outside of the casing spaced from the blower fan and between the latter and said shaft bearing operable by said shaft to create a cooling draft of air over said bearing, at least a portion of said means being exposed toward said bearing to permit direct circulation of air influenced by said means over the bearmg.

18. In a high temperature exhaust blower, a casing, a fan within the casing, a motor outside the casing for rotating said fan, a drive shaft connection between the motor and said fan, said drive shaft connection including portions spaced from each other, and a plurality of portionsbridging the space between 5 and connecting the first mentioned portions at different points thereabout.

19. In a high temperature exhaust blower, a casing, a fan within the casing, a motor outside the casing for rotating said fan, a m drive shaft connection between the motor and said fan. said drive shaft connection including portions spaced from each other, and a plurality of portions bridging the space be tween the first mentioned portions at differ- 3 ent points thereabout and extending outwardly thereof. v

20. In a high temperature exhaust blower, a casing. a fan within the casing. a motor outside the casing for rotating said fan. a drive shaft connection between the motor and said fan. said drive shaft connection including portions spaced from each other. and a pluralitv of members bridging the space between said portions atdifi'erent points thereabout and comprising portions of blade formation to create a circulation of air adjacent the said spaced portions of the drive shaft connection.

21. In a high temperature exhaust blower, a a casinsr, a fan in said casing. a drive shaft connection on which said fan is mounted extending outside the casing, a shaft bearing exteriorlv of said casing; and a cooler fan on said drive shaft connection spaced from Q the blower fan and between said shaft bearing and the blower fan, the blades of said cooler fan being located to be exposed and operate freely in the atmospheric area outside the casing. Q In testimony whereof I hereunto affix my signature.

HENRY W. PFEFFER. 

